JPWO2015025762A1 - Rubber composition and tire - Google Patents

Abstract

Provided are a rubber composition capable of obtaining a rubber molded article excellent in rolling resistance performance, steering stability, mechanical strength, and wear resistance, and a tire using at least a part of the rubber composition. 100 parts by mass of a rubber component (A) comprising a rubber component (A) comprising at least one of synthetic rubber and natural rubber, silica (B), and a modified polymer (C) of farnesene modified by introducing a functional group A rubber composition containing 20 to 150 parts by mass of silica (B) with respect to parts, and 2 to 10 parts by mass of the modified polymer (C) with respect to 100 parts by mass of silica (B).

Description

  The present invention relates to a rubber composition containing a polymer of a rubber component, silica, and farnesene, and a tire using at least a part of the rubber composition.

In recent years, rubber compositions containing silica have been studied in order to achieve both low fuel consumption performance and fracture characteristics of tires.
However, since silica has low dispersibility in the rubber composition, sufficient rolling resistance performance, mechanical strength, and abrasion resistance may not be obtained in the rubber composition after vulcanization.
In addition, in order to obtain a reinforcing property by combining silica and a rubber component, a silane coupling agent such as sulfide silane is generally used. However, in this case, a sufficient bond between silica and a rubber component cannot be obtained. In some cases, the rubber composition has low rigidity, that is, steering stability is insufficient.
In order to solve this problem, Patent Document 1 discloses a rubber composition in which a rubber component, silica, and a silane coupling agent having a specific molecular structure are blended at a predetermined ratio as a rubber composition in which each of the above characteristics is improved in a balanced manner. Has been proposed.
Although Patent Documents 2 and 3 describe polymers of β-farnesene, practical use has not been sufficiently studied.

JP 2009-120819 A International Publication No. 2010/027463 International Publication No. 2010/027464

According to the rubber composition described in Patent Document 1, although rolling resistance performance, steering stability, mechanical strength, and wear resistance can be improved to some extent, further improvements are desired for each characteristic.
The present invention has been made in view of the above circumstances, and a rubber composition capable of obtaining a rubber molded article excellent in rolling resistance performance, steering stability, mechanical strength, and wear resistance, and the rubber composition A tire using at least a part thereof is provided.

  As a result of intensive studies, the present inventors have found that a molded product of a rubber composition using a conjugated diene polymer having a specific structure is in rolling resistance performance, steering stability, mechanical strength, and wear resistance. As a result, the present invention was completed.

That is, the present invention relates to [1] and [2] below.
[1] A rubber component (A) composed of at least one of synthetic rubber and natural rubber, silica (B), and a modified polymer (C) of farnesene modified by introducing a functional group (hereinafter referred to as “modified polymer”) (C) "), 20 to 150 parts by mass of silica (B) per 100 parts by mass of rubber component (A), and the modified polymer (100 parts by mass of silica (B)). A rubber composition containing 2 to 10 parts by mass of C).
[2] A tire using at least a part of the rubber composition.

  According to the present invention, there are provided a rubber composition capable of obtaining a rubber molded article excellent in rolling resistance performance, steering stability, mechanical strength, and wear resistance, and a tire using at least a part of the rubber composition. it can.

[Rubber composition]
The rubber composition of the present invention includes a rubber component (A) composed of at least one of synthetic rubber and natural rubber, silica (B), and a modified polymer (C) of farnesene modified by introducing a functional group. 20 to 150 parts by mass of silica (B) is contained with respect to 100 parts by mass of the rubber component (A), and 2 to 10 parts by mass of the modified polymer (C) with respect to 100 parts by mass of the silica (B). To do.

<Rubber component (A)>
As the rubber component (A), rubber composed of at least one of synthetic rubber and natural rubber is used. Examples thereof include styrene butadiene rubber (hereinafter also referred to as “SBR”), butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, butadiene acrylonitrile copolymer rubber, chloroprene rubber, natural rubber, and the like. . Among these, SBR, butadiene rubber, isoprene rubber, and natural rubber are more preferable, and SBR and natural rubber are more preferable. These rubbers may be used alone or in combination of two or more.

[Synthetic rubber]
When synthetic rubber is used as the rubber component (A) in the present invention, SBR, butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, butadiene acrylonitrile copolymer rubber, chloroprene rubber and the like are preferable. , Isoprene rubber and butadiene rubber are more preferable, and SBR is more preferable.

(SBR (AI))
As the SBR, a general one used for a tire can be used. Specifically, the styrene content is preferably 0.1 to 70% by mass, more preferably 5 to 50% by mass, and 15 More preferred is ~ 35% by mass. Moreover, the thing whose vinyl content is 0.1-60 mass% is preferable, and a 0.1-55 mass% thing is more preferable.
The weight average molecular weight (Mw) of SBR is preferably 100,000 to 2,500,000, more preferably 150,000 to 2,000,000, and even more preferably 200,000 to 1,500,000. When it is in the above range, both workability and mechanical strength can be achieved.
In addition, Mw in this specification is the value measured by the method as described in the below-mentioned Example.
The glass transition temperature (Tg) obtained by differential thermal analysis of SBR used in the present invention is preferably in the range of −95 to 0 ° C., more preferably in the range of −95 to −5 ° C. . By setting Tg within the above range, it is possible to suppress an increase in viscosity and to facilitate handling.

≪SBR manufacturing method≫
The SBR that can be used in the present invention is obtained by copolymerizing styrene and butadiene. There is no restriction | limiting in particular about the manufacturing method of SBR, and any of an emulsion polymerization method, a solution polymerization method, a gas phase polymerization method, and a bulk polymerization method can be used, and an emulsion polymerization method and a solution polymerization method are especially preferable.

(I) Emulsion polymerization styrene butadiene rubber (E-SBR)
E-SBR can be produced by an ordinary emulsion polymerization method. For example, a predetermined amount of styrene and butadiene monomers are emulsified and dispersed in the presence of an emulsifier, and emulsion polymerization is performed using a radical polymerization initiator.
As the emulsifier, for example, a long chain fatty acid salt or rosin acid salt having 10 or more carbon atoms is used. Specific examples include potassium salts or sodium salts of fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, oleic acid and stearic acid.
As the dispersant, water is usually used, and it may contain a water-soluble organic solvent such as methanol and ethanol as long as the stability during polymerization is not inhibited.
Examples of the radical polymerization initiator include persulfates such as ammonium persulfate and potassium persulfate, organic peroxides, hydrogen peroxide, and the like.
In order to adjust the molecular weight of the obtained E-SBR, a chain transfer agent can also be used. Examples of the chain transfer agent include mercaptans such as t-dodecyl mercaptan and n-dodecyl mercaptan; carbon tetrachloride, thioglycolic acid, diterpene, terpinolene, γ-terpinene, α-methylstyrene dimer, and the like.

Although the temperature of emulsion polymerization can be suitably selected according to the kind of radical polymerization initiator to be used, 0-100 degreeC is preferable normally and 0-60 degreeC is more preferable. The polymerization mode may be either continuous polymerization or batch polymerization. The polymerization reaction can be stopped by adding a polymerization terminator.
Examples of the polymerization terminator include amine compounds such as isopropylhydroxylamine, diethylhydroxylamine, and hydroxylamine; quinone compounds such as hydroquinone and benzoquinone, and sodium nitrite.
After termination of the polymerization reaction, an antioxidant may be added as necessary. After the polymerization reaction is stopped, unreacted monomers are removed from the obtained latex as necessary, and then a salt such as sodium chloride, calcium chloride, potassium chloride is used as a coagulant, and nitric acid, sulfuric acid, etc. The polymer can be recovered as crumbs by adding the acid and coagulating the polymer while adjusting the pH of the coagulation system to a predetermined value and then separating the dispersion solvent. E-SBR can be obtained by washing the crumb with water, followed by dehydration and drying with a band dryer or the like. In addition, at the time of coagulation, if necessary, a latex and an extending oil that has been made into an emulsified dispersion may be mixed and recovered as an oil-extended rubber.
Examples of commercially available E-SBR include oil-extended styrene butadiene rubber “JSR1723” manufactured by JSR Corporation.

(Ii) Solution-polymerized styrene butadiene rubber (S-SBR)
S-SBR can be produced by an ordinary solution polymerization method. For example, an active metal capable of anion polymerization in a solvent is used, and styrene and butadiene are polymerized in the presence of a polar compound as desired.
Examples of the anion-polymerizable active metal include alkali metals such as lithium, sodium and potassium; alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium; lanthanoid rare earth metals such as lanthanum and neodymium . Of these, alkali metals and alkaline earth metals are preferable, and alkali metals are more preferable. Further, among alkali metals, organic alkali metal compounds are more preferably used.
Examples of the solvent include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane and isooctane; alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; benzene, And aromatic hydrocarbons such as toluene. These solvents are preferably used in a range where the monomer concentration is 1 to 50% by mass.

Examples of the organic alkali metal compound include organic monolithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenelithium; dilithiomethane, 1,4-dilithiobutane, 1,4 -Polyfunctional organic lithium compounds such as dilithio-2-ethylcyclohexane and 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene and the like. Among these, an organic lithium compound is preferable, and an organic monolithium compound is more preferable. The amount of the organic alkali metal compound used is appropriately determined depending on the required molecular weight of S-SBR.
The organic alkali metal compound can also be used as an organic alkali metal amide by reacting with a secondary amine such as dibutylamine, dihexylamine, and dibenzylamine.
The polar compound is not particularly limited as long as it is usually used for adjusting the microstructure of the butadiene site and the distribution in the copolymer chain of styrene without deactivating the reaction in anionic polymerization. Examples include ether compounds such as dibutyl ether, tetrahydrofuran and ethylene glycol diethyl ether; tertiary amines such as tetramethylethylenediamine and trimethylamine; alkali metal alkoxides and phosphine compounds.

The temperature of the polymerization reaction is usually in the range of −80 to 150 ° C., preferably 0 to 100 ° C., more preferably 30 to 90 ° C. The polymerization mode may be either a batch type or a continuous type. In order to improve the random copolymerization of styrene and butadiene, styrene and butadiene are continuously or intermittently supplied into the reaction solution so that the composition ratio of styrene and butadiene in the polymerization system falls within a specific range. Is preferred.
The polymerization reaction can be stopped by adding an alcohol such as methanol or isopropanol as a polymerization terminator. Coupling of tin tetrachloride, tetrachlorosilane, tetramethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolylene diisocyanate, etc. that can react with the polymerization active terminal before adding the polymerization terminator An agent, or a polymerization terminal modifier such as 4,4′-bis (diethylamino) benzophenone or N-vinylpyrrolidone may be added. The polymerization solution after termination of the polymerization reaction can recover the target S-SBR by separating the solvent by direct drying, steam stripping or the like. In addition, before removing the solvent, the polymerization solution and the extending oil may be mixed in advance and recovered as an oil-extended rubber.

(Iii) Modified styrene butadiene rubber (modified SBR)
In the present invention, modified SBR in which a functional group is introduced into SBR may be used. Examples of the functional group include an amino group, an alkoxysilyl group, a hydroxy group, an epoxy group, and a carboxyl group.
As a method for producing the modified SBR, for example, before adding a polymerization terminator, tin tetrachloride, tetrachlorosilane, dimethyldichlorosilane, dimethyldiethoxysilane, tetramethoxysilane, tetraethoxysilane, which can react with a polymerization active terminal, Coupling agents such as 3-aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolylene diisocyanate, 4,4′-bis (diethylamino) benzophenone, N-vinylpyrrolidone, etc. And a method of adding other modifiers described in JP-A-2011-132298.
In this modified SBR, the position of the polymer into which the functional group is introduced may be the polymerization terminal or the side chain of the polymer chain.

(Isoprene rubber (A-II))
Examples of the isoprene rubber include Ziegler catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel; -Commercially available isoprene rubber polymerized by using a lanthanoid rare earth metal catalyst such as an organic acid neodymium-Lewis acid type or an organic alkali metal compound in the same manner as S-SBR can be used. Isoprene rubber polymerized with a Ziegler catalyst is preferred because of its high cis isomer content. Further, isoprene rubber having an ultra-high cis body content obtained using a lanthanoid rare earth metal catalyst may be used.

The vinyl content of the isoprene rubber is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less. When the vinyl content exceeds 50% by mass, the rolling resistance performance tends to deteriorate. The lower limit of the vinyl content is not particularly limited. The glass transition temperature varies depending on the vinyl content, but is preferably −20 ° C. or lower, and more preferably −30 ° C. or lower.
The weight average molecular weight (Mw) of isoprene rubber is preferably 90,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When Mw is in the above range, workability and mechanical strength are good.
The isoprene rubber is partly composed of a polyfunctional modifier such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an amino group-containing alkoxysilane. It may have a branched structure or a polar functional group.

(Butadiene rubber (A-III))
Examples of the butadiene rubber include Ziegler catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel; -Commercially available butadiene rubber polymerized using a lanthanoid rare earth metal catalyst such as organic acid neodymium-Lewis acid or the like, or an organic alkali metal compound in the same manner as S-SBR can be used. Butadiene rubber polymerized with a Ziegler catalyst is preferred because of its high cis isomer content. Moreover, you may use the butadiene rubber of the ultra high cis body content obtained using a lanthanoid type rare earth metal catalyst.
The vinyl content of the butadiene rubber is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less. When the vinyl content exceeds 50% by mass, the rolling resistance performance tends to deteriorate. The lower limit of the vinyl content is not particularly limited. The glass transition temperature varies depending on the vinyl content, but is preferably −40 ° C. or lower, and more preferably −50 ° C. or lower.
The weight average molecular weight (Mw) of the butadiene rubber is preferably 90,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When Mw is in the above range, workability and mechanical strength are good.
A part of the butadiene rubber is a polyfunctional type modifier such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an amino group-containing alkoxysilane. It may have a branched structure or a polar functional group.

Along with at least one of SBR, isoprene rubber, and butadiene rubber, one or more of butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, butadiene acrylonitrile copolymer rubber, chloroprene rubber and the like can be used. Moreover, these manufacturing methods are not specifically limited, What is marketed can be used.
In the present invention, by using SBR, isoprene rubber, butadiene rubber and other synthetic rubbers together with silica (B) and farnesene modified polymer (C) described later, rolling resistance performance, steering stability, mechanical strength, Abrasion can be improved.
When two or more kinds of synthetic rubbers are mixed and used, the combination can be arbitrarily selected within a range not impairing the effects of the present invention, and the physical properties such as rolling resistance performance and wear resistance can be adjusted by the combination.

[Natural rubber]
Examples of the natural rubber used in the rubber component (A) include TSR such as SMR, SIR, and STR, natural rubber generally used in the tire industry such as RSS, high-purity natural rubber, epoxidized natural rubber, and hydroxylation. Examples thereof include modified natural rubber such as natural rubber, hydrogenated natural rubber, and grafted natural rubber. Among these, SMR20, STR20, and RSS # 3 are preferable from the viewpoint of little variation in quality and easy availability. These may be used alone or in combination of two or more.
In addition, there is no restriction | limiting in particular in the manufacturing method of the rubber | gum used for a rubber component (A), You may use a commercially available thing.
In this invention, 20-99.9 mass% is preferable, as for content of the rubber component (A) in a rubber composition, 25-80 mass% is more preferable, and 30-70 mass% is still more preferable.
In the present invention, rolling resistance performance, steering stability, mechanical strength, and wear resistance can be improved by using natural rubber, silica (B), which will be described later, and a modified polymer (C) of farnesene.

<Silica (B)>
Examples of the silica (B) include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate and the like. Among these, wet silica is preferable from the viewpoint of further improving mechanical strength and wear resistance. These may be used alone or in combination of two or more.
The average particle diameter of silica is preferably from 0.5 to 200 nm, more preferably from 5 to 150 nm, from the viewpoint of improving processability, rolling resistance performance, mechanical strength, and wear resistance of the rubber composition obtained. 100 nm is more preferable.
The average particle diameter of silica can be determined by measuring the diameter of the particles with a transmission electron microscope and calculating the average value.
The content of silica (B) is 20 to 150 parts by mass and 30 to 130 parts by mass with respect to 100 parts by mass of the rubber component (A) from the viewpoint of improving rolling resistance performance, mechanical strength, and wear resistance. Is preferable, and 40-120 mass parts is more preferable.

<Modified polymer of farnesene modified by introducing functional group (C)>
The rubber composition of the present invention contains a modified polymer (C) (modified polymer (C)) of farnesene modified by introducing a functional group. In the present invention, since the rubber component (A), silica (B), and modified polymer (C) are used in combination, a rubber molded product excellent in rolling resistance performance, steering stability, mechanical strength, and wear resistance is provided. A rubber composition that can be obtained can be obtained.
As farnesene constituting the modified polymer (C) in the present invention, at least one of α-farnesene and β-farnesene represented by the formula (I) can be used, from the viewpoint of ease of production of the modified polymer, From the viewpoint of improving rolling resistance performance, it is preferable to use β-farnesene.

  The modified polymer (C) can be produced, for example, by producing a farnesene polymer (hereinafter also referred to as “unmodified polymer”) and introducing a functional group into the unmodified polymer.

(Method for producing unmodified polymer)
The unmodified polymer can be produced by an emulsion polymerization method, a method described in International Publication No. 2010/027463, International Publication No. 2010/027464, or the like. Among these, an emulsion polymerization method or a solution polymerization method is preferable, and a solution polymerization method is more preferable.

As an emulsion polymerization method for obtaining an unmodified polymer, a known method can be applied. For example, a predetermined amount of farnesene monomer is emulsified and dispersed in the presence of an emulsifier, and emulsion polymerization is performed using a radical polymerization initiator.
As the emulsifier, for example, a long chain fatty acid salt or rosin acid salt having 10 or more carbon atoms is used. Specific examples include potassium salts or sodium salts of fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, oleic acid and stearic acid.
As the dispersant, water is usually used, and it may contain a water-soluble organic solvent such as methanol and ethanol as long as the stability during polymerization is not inhibited.
Examples of the radical polymerization initiator include persulfates such as ammonium persulfate and potassium persulfate, organic peroxides, and hydrogen peroxide.
A chain transfer agent can also be used to adjust the molecular weight of the resulting unmodified polymer. Examples of the chain transfer agent include mercaptans such as t-dodecyl mercaptan and n-dodecyl mercaptan; carbon tetrachloride, thioglycolic acid, diterpene, terpinolene, γ-terpinene, α-methylstyrene dimer, and the like.
The emulsion polymerization temperature can be appropriately selected depending on the type of the radical polymerization initiator to be used, but is usually preferably 0 to 100 ° C, more preferably 0 to 60 ° C. The polymerization mode may be either continuous polymerization or batch polymerization. The polymerization reaction can be stopped by adding a polymerization terminator.

Examples of the polymerization terminator include amine compounds such as isopropylhydroxylamine, diethylhydroxylamine, and hydroxylamine, quinone compounds such as hydroquinone and benzoquinone, and sodium nitrite.
After termination of the polymerization reaction, an antioxidant may be added as necessary. After the polymerization reaction is stopped, unreacted monomers are removed from the obtained latex as necessary, and then a salt such as sodium chloride, calcium chloride, potassium chloride is used as a coagulant, and nitric acid, sulfuric acid, etc. The unmodified polymer is coagulated while adjusting the pH of the coagulation system to a predetermined value by adding an acid, and then the unmodified polymer is recovered by separating the dispersion solvent. Next, after washing with water and dehydration, drying is performed to obtain an unmodified polymer. In addition, during the coagulation, if necessary, latex and an extending oil that has been made into an emulsified dispersion may be mixed and recovered as an oil-modified unmodified polymer.

As a solution polymerization method for obtaining an unmodified polymer, a known method can be applied. For example, a farnesene monomer is polymerized in a solvent using a Ziegler catalyst, a metallocene catalyst, and an anion-polymerizable active metal, if desired, in the presence of a polar compound.
Examples of the anion-polymerizable active metal include alkali metals such as lithium, sodium and potassium; alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium; lanthanoid rare earth metals such as lanthanum and neodymium . Of these, alkali metals and alkaline earth metals are preferable, and alkali metals are more preferable. Further, among alkali metals, organic alkali metal compounds are more preferably used.
Examples of the solvent include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane and isooctane; alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; benzene, Aromatic hydrocarbons such as toluene and xylene are exemplified.
Examples of the organic alkali metal compound include organic monolithium compounds such as methyllithium, ethyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, hexyllithium, phenyllithium, stilbenelithium; dilithiomethane, dilithionaphthalene Polyfunctional organolithium compounds such as 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene and the like. Among these, an organic lithium compound is preferable, and an organic monolithium compound is more preferable. The amount of the organic alkali metal compound used is appropriately determined according to the required molecular weight of the farnesene polymer, but is preferably 0.01 to 3 parts by mass with respect to 100 parts by mass of farnesene.
The organic alkali metal compound can also be used as an organic alkali metal amide by reacting with a secondary amine such as dibutylamine, dihexylamine, dibenzylamine and the like.

The polar compound is used to adjust the microstructure of the farnesene moiety in anionic polymerization without deactivating the reaction. For example, ether compounds such as dibutyl ether, tetrahydrofuran, ethylene glycol diethyl ether; tetramethylethylenediamine, trimethylamine, etc. Tertiary amines; alkali metal alkoxides, phosphine compounds and the like. The polar compound is preferably used in an amount of 0.01 to 1000 molar equivalents relative to the organic alkali metal compound.
The temperature of the polymerization reaction is usually in the range of −80 to 150 ° C., preferably 0 to 100 ° C., more preferably 10 to 90 ° C. The polymerization mode may be either batch or continuous.

(Configuration of unmodified polymer)
The unmodified polymer may be composed of only the monomer unit (c1) derived from β-farnesene, and the monomer unit (c1) derived from β-farnesene and a monomer other than β-farnesene. You may be comprised with the monomer unit (c2) derived.
When the modified polymer is a copolymer, examples of the monomer unit (c2) derived from monomers other than β-farnesene include conjugated dienes having 12 or less carbon atoms and aromatic vinyl compounds. it can.
Examples of the conjugated diene having 12 or less carbon atoms include butadiene, isoprene, 2,3-dimethyl-butadiene, 2-phenyl-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3- Examples include hexadiene, 1,3-octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, myrcene, chloroprene and the like. Of these, butadiene, isoprene, and myrcene are more preferable. These conjugated dienes may be used alone or in combination of two or more.

  Examples of the aromatic vinyl compound include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-t-butylstyrene, 4-cyclohexylstyrene, 4- Dodecylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 2,4,6-trimethylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene, 1-vinylnaphthalene, 2- Aromatic vinyl compounds such as vinylnaphthalene, vinylanthracene, N, N-diethyl-4-aminoethylstyrene, vinylpyridine, 4-methoxystyrene, monochlorostyrene, dichlorostyrene, divinylbenzene, and the like can be given. Among these, styrene, α-methylstyrene, and 4-methylstyrene are preferable.

  The ratio of the monomer unit (c2) to the total of the monomer unit (c2) derived from a monomer other than β-farnesene and the monomer unit (c1) derived from β-farnesene in the copolymer is as follows: From the viewpoint of improving the workability and rolling resistance performance of the resulting rubber composition, 1 to 99 mass% is preferable, 10 to 80 mass% is more preferable, and 15 to 80 mass% is still more preferable. Moreover, from a viewpoint of improving abrasion resistance, 40-80 mass% is preferable and, as for the ratio of a monomer unit (c2), 60-80 mass% is more preferable. From the viewpoint of improving processability, the proportion of the monomer unit (c2) is preferably 20 to 60% by mass, and more preferably 20 to 40% by mass.

  The monomer unit (c2) derived from monomers other than β-farnesene is more preferably butadiene from the viewpoint of improving rolling resistance performance and wear resistance.

[Modification method of unmodified polymer]
The modified polymer (C) is a method of adding a modifying agent such as tetraethoxysilane, carbon dioxide, ethylene oxide or the like that can react with a polymerization active terminal to the unmodified polymer before adding a polymerization terminator ( It can be obtained by a modification method such as I) or a method (II) of grafting a modifier such as maleic anhydride onto an unmodified polymer after adding a polymerization terminator.

Examples of the functional group introduced into the unmodified farnesene polymer include an amino group, an ammonium group, an amide group, an imino group, an imidazole group, a urea group, an alkoxysilyl group, a silanol group, a hydroxy group, an epoxy group, and an ether. Group, carboxy group, carbonyl group, carboxylic acid ester group, sulfonic acid group, sulfonic acid ester group, phosphoric acid group, phosphoric ester group, mercapto group, isocyanate group, nitrile group, silicon halide group, tin halide group, Examples include functional groups derived from acid anhydrides. Among these, 1 type or 2 or more types chosen from the functional group derived from a carboxy group, an amino group, a hydroxy group, and an acid anhydride are preferable, As a functional group derived from an acid anhydride, a functional group derived from maleic anhydride Is more preferable.
In addition, about the position of the polymer in which a functional group is introduce | transduced in a modified polymer, a polymerization terminal may be sufficient and the side chain of a polymer chain may be sufficient.

Examples of the modifier that can be used in the method (I) include dimethyldiethoxysilane, tetramethoxysilane, tetraethoxysilane, 3-aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane. 2,4-tolylene diisocyanate, carbon dioxide, ethylene oxide, succinic anhydride, 4,4′-bis (diethylamino) benzophenone, N-vinylpyrrolidone, N-methylpyrrolidone, 4-dimethylaminobenzylideneaniline, dimethylimidazolide Non-modifying agents such as non-modified or other modifying agents described in JP2011-132298A can be mentioned.
The modifying agent is preferably in the range of 0.01 to 100 molar equivalents relative to the organoalkali metal compound, and the reaction temperature is usually −80 to 150 ° C., preferably 0 to 100 ° C., more preferably 10 to 90. It is in the range of ° C.
Further, before adding a polymerization terminator, after adding the above-mentioned modifier and introducing a functional group into the unmodified polymer, a modifier capable of reacting with the functional group is further added to introduce another functional group into the polymer. May be introduced.

  Examples of the modifier that can be used in the method (II) include unsaturated carboxylic acid anhydrides such as maleic anhydride, citraconic anhydride, 2,3-dimethylmaleic anhydride and itaconic anhydride; maleic acid and fumaric acid Unsaturated carboxylic acids such as citraconic acid and itaconic acid; unsaturated carboxylic acid esters such as maleic acid ester, fumaric acid ester, citraconic acid ester and itaconic acid ester; maleic acid amide, fumaric acid amide, citraconic acid amide and itaconic acid Unsaturated carboxylic acid amides such as amides; Unsaturated carboxylic acid imides such as maleic imides, fumaric imides, citraconic imides, itaconic imides; maleimides, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, etc. It is done.

  In the method (II), the method for grafting the modifying agent to the unmodified farnesene polymer is not particularly limited. For example, the unmodified farnesene polymer, the modifying agent, and a radical catalyst as necessary are added. Thus, a method of heating in the presence or absence of an organic solvent can be employed. Examples of the organic solvent used in the above method generally include hydrocarbon solvents and halogenated hydrocarbon solvents. Among these organic solvents, hydrocarbon solvents such as n-butane, n-hexane, n-heptane, cyclohexane, benzene, toluene and xylene are preferable.

The modifier is preferably used in the range of 0.1 to 100 parts by mass, more preferably 0.5 to 50 parts by mass with respect to 100 parts by mass of the unmodified polymer. The reaction temperature is usually preferably in the range of 0 to 200 ° C, more preferably in the range of 50 to 200 ° C. Moreover, when performing reaction which introduce | transduces a modifier | denaturant, you may add an anti-aging agent from a viewpoint etc. which suppress a side reaction.
Further, after introducing a functional group by grafting a modifier to the unmodified polymer, another functional group may be introduced into the polymer by adding a modifier capable of reacting with the functional group. Specifically, after grafting a carboxylic anhydride to an unmodified polymer obtained by living anion polymerization, a method of reacting a compound such as 2-hydroxyethyl methacrylate, methanol, water, ammonia, amine, etc. Can be mentioned.

  A modified polymer having a functional group such as a dicarboxylic acid group, a dicarboxylic acid monoester group, or a dicarboxylic acid monoamide group by reacting these compounds to cause a ring-opening reaction of the carboxylic anhydride moiety in the modified polymer (C). (C) can be obtained. In the case of producing a modified polymer (C) obtained by subjecting the carboxylic anhydride moiety in the modified polymer (C) to a ring-opening reaction to produce a secondary modification, the amount of the above-mentioned compound used for the ring-opening reaction is the amount of anhydride in the polymer. 0.5-5 mol equivalent is preferable with respect to a carboxylic acid group, and 0.8-5 mol equivalent is more preferable. By performing the above modification, the elastic modulus is increased and the steering stability is improved.

  The reaction rate of the modifier with respect to the modified polymer (C) is preferably 40 to 100%, more preferably 60 to 100%, and still more preferably 80 to 100%. When the reaction rate of the modifier is within the above range, rolling resistance performance, mechanical strength, hardness, and wear resistance are good. The reaction rate of the modifier can be calculated as a ratio of the amount introduced into the polymer with respect to the total amount of modifier charged during the modification reaction.

The weight average molecular weight (Mw) of the modified polymer (C) is preferably from 2,000 to 500,000, more preferably from 8,000 to 500,000, further preferably from 15,000 to 450,000, and even more preferably from 30,000 to 300,000. preferable. When the Mw of the modified polymer (C) is within the above range, the processability of the rubber composition of the present invention is improved, and the dispersibility of silica in the resulting rubber composition is improved, so that the rolling resistance performance is improved. It becomes good.
When the weight average molecular weight (Mw) of the modified polymer (C) is 30,000 or more, crosslinking with the rubber component in the rubber composition is likely to occur, so that the wear resistance is improved.
In the present specification, the Mw of the modified polymer (C) is a value determined by the method described in Examples described later.
In the present invention, two types of modified polymers (C) having different Mw may be used in combination.
When the modified polymer is a copolymer, the weight average molecular weight (Mw) is preferably 2,000 to 500,000, more preferably 8,000 to 300,000, from the viewpoint of further improving the rolling resistance performance. 200,000 is more preferable, and 20,000 to 100,000 is more preferable.

  The melt viscosity at 38 ° C. of the modified polymer (C) is preferably 0.1 to 3,000 Pa · s, more preferably 1.0 to 2,000 Pa · s, and further preferably 2.5 to 1,500 Pa · s. It is preferably 4.0 to 1,000 Pa · s. When the melt viscosity of the modified polymer (C) is within the above range, kneading of the resulting rubber composition becomes easy and processability is improved. In the present specification, the melt viscosity of the modified polymer (C) is a value determined by the method described in Examples described later.

  The molecular weight distribution (Mw / Mn) of the modified polymer (C) is preferably 1.0 to 8.0, more preferably 1.0 to 5.0, and still more preferably 1.0 to 3.0. It is more preferable that Mw / Mn is in the above-mentioned range because the resulting modified polymer (C) has a small variation in viscosity.

  The glass transition temperature of the modified polymer (C) is preferably -90 to 10 ° C, more preferably -90 to 0 ° C, still more preferably -90 to -5 ° C. When it is in the above range, the rolling resistance performance is good. Moreover, it can suppress that a viscosity becomes high and can handle it easily.

  The amount of functional group (modifier amount) added to the modified polymer (C) is preferably 0.1 to 100 parts by mass, and 0.2 to 50 parts by mass with respect to 100 parts by mass of the unmodified polymer. Part. When the amount of the functional group added to the modified polymer (C) is within the above range, rolling resistance performance, mechanical strength, hardness, and wear resistance are improved. The amount of functional group added to the modified polymer (C) can be calculated based on the reaction rate of the modifier, or can be determined by the method described in the examples described later.

The average number of functional groups per molecule of the modified polymer (C) is 0.1 to 300, preferably 3 to 250, and more preferably 5 to 200. When the average number of functional groups is within the above range, the dispersibility of silica (B) in the resulting rubber composition is improved, so that the rolling resistance performance of a tire or the like made of the crosslinked product is improved, and the tire is further deformed. Small and excellent in handling stability. In addition, the wear resistance of the crosslinked product obtained from the rubber composition is further improved.
The average number of functional groups per molecule of the modified polymer (C) can be determined by ¹ H-NMR described later.

The functional group equivalent of the modified polymer (C) is preferably in the range of 150 to 6,500 g / eq, more preferably 200 to 5,000 g / eq, and 300 to 3,000 g / eq. More preferably. Since the dispersibility of the silica (B) in the resulting rubber composition is improved when the equivalent of the functional group of the modified polymer (C) is in the above range, the rolling resistance performance of a tire made of the crosslinked product, etc. In addition, tire deformation is small and steering stability is excellent. In addition, the wear resistance of the crosslinked product obtained from the rubber composition is further improved.
In addition, the equivalent of the functional group in the present specification means the mass of farnesene bonded per functional group and other monomers other than farnesene contained as necessary. The equivalent of the functional group is calculated from the area ratio of the peak derived from the functional group and the peak derived from the polymer main chain using ¹ H-NMR or ¹³ C-NMR, or calculated by acid value measurement described later. Can do.

  In this modified polymer (C), the position at which the functional group is introduced may be a polymerization terminal or a side chain of the polymer chain, but a viewpoint that a plurality of functional groups can be easily introduced. Thus, it is preferably a side chain of a polymer chain. Moreover, the said functional group may be contained individually by 1 type, and may be contained 2 or more types. Therefore, the modified polymer (C) may be modified with one modified compound, or may be modified with two or more modified compounds.

  In this invention, content of the modified polymer (C) with respect to 100 mass parts of silica (B) is 2-10 mass parts, and 2.5-9.5 mass parts is preferable. When the content of the modified polymer (C) is within the above range, the mechanical strength and rolling resistance performance are good. In addition, it has excellent wear resistance, and when used in a tire or the like, the deformation of the tire is small, and the steering stability can be improved.

<Filler>
The rubber composition of the present invention may contain a filler such as carbon black other than silica.
〔Carbon black〕
As the carbon black, for example, carbon black such as furnace black, channel black, thermal black, acetylene black, and ketjen black can be used. Among these, furnace black is preferable from the viewpoint of improving the vulcanization speed and mechanical strength.
The average particle size of the carbon black is preferably 5 to 100 nm, more preferably 5 to 80 nm, and still more preferably 5 to 70 nm, from the viewpoint of improving dispersibility, mechanical strength, and hardness.
As carbon black having an average particle diameter of 5 to 100 nm, examples of furnace black commercial products include “Dia Black” manufactured by Mitsubishi Chemical Corporation, “Shiest” manufactured by Tokai Carbon Co., Ltd., and the like. Examples of commercially available acetylene black include “DENKA BLACK” manufactured by Denki Kagaku Kogyo Co., Ltd. Examples of commercially available ketjen black include “ECP600JD” manufactured by Lion Corporation.

From the viewpoint of improving the wettability and dispersibility to the rubber component (A) and the modified polymer (C), the above-described carbon black is subjected to acid treatment with nitric acid, sulfuric acid, hydrochloric acid or a mixed acid thereof, or in the presence of air. Surface oxidation treatment by heat treatment in may be performed. Moreover, you may heat-process at 2,000-3,000 degreeC in presence of a graphitization catalyst from a viewpoint of the mechanical strength improvement of the rubber composition of this invention. Examples of the graphitization catalyst include boron, boron oxide (for example, B ₂ O ₂ , B ₂ O ₃ , B ₄ O ₃ , B ₄ O ₅ ), boron oxoacid (for example, orthoboric acid, metaboric acid, Tetraboric acid etc.) and salts thereof, boron carbide (eg B ₄ C, B ₆ C etc.), boron nitride (BN), and other boron compounds are preferably used.

The particle size of carbon black can be adjusted by pulverization or the like. For carbon black pulverization, high-speed rotary pulverizer (hammer mill, pin mill, cage mill), various ball mills (rolling mill, vibration mill, planetary mill), stirring mill (bead mill, attritor, distribution pipe mill, annular mill) Etc. can be used.
The average particle size of carbon black can be determined by measuring the particle diameter with a transmission electron microscope and calculating the average value.

[Other fillers]
The rubber composition of the present invention may further contain a filler other than silica and carbon black, if necessary, for the purpose of improving mechanical strength, adjusting hardness, improving economy by blending an extender, and the like. Good.

The filler other than silica and carbon black is appropriately selected according to the application, for example, organic filler, clay, talc, mica, calcium carbonate, magnesium hydroxide, aluminum hydroxide, barium sulfate, titanium oxide, One or more inorganic fillers such as glass fiber, fibrous filler, and glass balloon can be used.
When the rubber composition of the present invention contains the filler, the content thereof is preferably 0.1 to 120 parts by mass, more preferably 5 to 90 parts by mass with respect to 100 parts by mass of the rubber component (A). 10-80 mass parts is still more preferable. When the content of the filler is within the above range, the mechanical strength is further improved.

<Vulcanizing agent>
The rubber composition of the present invention preferably contains a vulcanizing agent. Examples of the vulcanizing agent include sulfur and sulfur compounds. These may be used alone or in combination of two or more. The content of the vulcanizing agent is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 10 parts by mass, and further 0.8 to 5 parts by mass with respect to 100 parts by mass of the rubber component (A). preferable.

<Vulcanization accelerator>
The rubber composition of the present invention may contain a vulcanization accelerator. Examples of the vulcanization accelerator include guanidine compounds, sulfenamide compounds, thiazole compounds, thiuram compounds, thiourea compounds, dithiocarbamic acid compounds, aldehyde-amine compounds or aldehyde-ammonia compounds, imidazolines. Compounds, xanthate compounds, and the like. These may be used alone or in combination of two or more. When it contains the said vulcanization accelerator, 0.1-15 mass parts is preferable with respect to 100 mass parts of rubber components (A), and 0.1-10 mass parts is more preferable.

<Vulcanization aid>
The rubber composition of the present invention may contain a vulcanization aid. Examples of the vulcanization aid include fatty acids such as stearic acid, metal oxides such as zinc white, and fatty acid metal salts such as zinc stearate. These may be used alone or in combination of two or more. When the said vulcanization | cure adjuvant is contained, 0.1-15 mass parts is preferable with respect to 100 mass parts of rubber components (A), and 1-10 mass parts is more preferable.

<Silane coupling agent>
The rubber composition of the present invention preferably contains a silane coupling agent. Examples of the silane coupling agent include sulfide compounds, mercapto compounds, vinyl compounds, amino compounds, glycidoxy compounds, nitro compounds, and chloro compounds.
Examples of sulfide compounds include bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, and bis (2-trimethoxy). Silylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) Disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N, -Dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, etc. Can be mentioned.
Examples of the mercapto compound include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and the like.
Examples of the vinyl compound include vinyl triethoxysilane and vinyl trimethoxysilane.
Examples of amino compounds include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, and 3- (2-aminoethyl) aminopropyltrimethoxy. Silane etc. are mentioned.
Examples of glycidoxy compounds include γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-glycidoxypropylmethyldimethoxysilane. Can be mentioned.
Examples of the nitro compound include 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane.
Examples of the chloro compound include 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, and the like.
These silane coupling agents may be used alone or in combination of two or more. Of these, silane coupling agents containing sulfur such as sulfide compounds and mercapto compounds are preferred from the viewpoint of a large reinforcing effect, and bis (3-triethoxysilylpropyl) disulfide and bis (3-triethoxysilylpropyl) tetra Sulfide and 3-mercaptopropyltrimethoxysilane are more preferable.

  0.1-30 mass parts is preferable, as for content of the said silane coupling agent with respect to 100 mass parts of silica (B), 0.5-20 mass parts is more preferable, and 1-15 mass parts is still more preferable. When the content of the silane coupling agent is within the above range, dispersibility, reinforcement, and abrasion resistance are improved.

<Other ingredients>
The rubber composition of the present invention is intended to improve processability, fluidity and the like within a range that does not impair the effects of the invention, and if necessary, silicon oil, aroma oil, TDAE (Treated Distilled Aromatic Extracts), MES (Mild) Extracted Solvates), RAE (Residual Aromatic Extracts), paraffin oil, naphthenic oil and other process oils, aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, C9 resins, rosin resins, coumarone / indene resins, phenolic resins Resin component such as resin, low molecular weight polybutadiene, low molecular weight polyisoprene, low molecular weight styrene butadiene copolymer, liquid polymer such as low molecular weight styrene isoprene copolymer, unmodified polymer may be included as a softening agent . The copolymer may be in any polymerization form such as block or random. The weight average molecular weight (Mw) of the liquid polymer is preferably 500 to 100,000 from the viewpoint of processability. When the rubber composition of the present invention contains the above process oil, resin component or liquid polymer, and unmodified polymer as a softening agent, the content is from 50 parts by mass with respect to 100 parts by mass of the rubber component (A). Less is preferred.

The rubber composition of the present invention is an anti-aging agent, an antioxidant, a wax, a lubricant, a light as needed for the purpose of improving the weather resistance, heat resistance, oxidation resistance, etc., as long as the effects of the invention are not impaired. Stabilizers, scorch inhibitors, processing aids, colorants such as pigments and dyes, flame retardants, antistatic agents, matting agents, antiblocking agents, UV absorbers, mold release agents, foaming agents, antibacterial agents, fungicides 1 type, or 2 or more types of additives, such as an agent and a fragrance | flavor, may be contained.
Examples of the antioxidant include hindered phenol compounds, phosphorus compounds, lactone compounds, hydroxyl compounds, and the like.
Examples of the antiaging agent include amine-ketone compounds, imidazole compounds, amine compounds, phenolic compounds, sulfur compounds, and phosphorus compounds.

  The rubber composition of the present invention can be used after being vulcanized by using the above vulcanizing agent and by being crosslinked by adding a crosslinking agent. Examples of the cross-linking agent include oxygen, organic peroxide, phenol resin and amino resin, quinone and quinonedioxime derivatives, halogen compounds, aldehyde compounds, alcohol compounds, epoxy compounds, metal halides and organometallic halides, and silane compounds. Etc. These may be used alone or in combination of two or more. As for content of a crosslinking agent, 0.1-10 mass parts is preferable with respect to 100 mass parts of rubber components (A).

  The method for producing the rubber composition of the present invention is not particularly limited, and the components may be mixed uniformly. As a method of uniformly mixing, for example, a tangential or meshing closed kneader such as a kneader ruder, brabender, banbury mixer, internal mixer, single screw extruder, twin screw extruder, mixing roll, roller, etc. Usually, and can be performed in a temperature range of 70 to 270 ° C.

  The rubber composition of the present invention can also be used as a vulcanized rubber by vulcanization. There are no particular restrictions on the vulcanization conditions and method, but it is preferably carried out using a vulcanization mold under a vulcanization temperature of 120 to 200 ° C. and a vulcanization pressure of 0.5 to 2.0 MPa.

[tire]
The tire of the present invention uses at least a part of the rubber composition of the present invention. Therefore, the mechanical strength is good and it has excellent rolling resistance performance. Furthermore, the tire using the rubber composition of the present invention can maintain the characteristics such as the mechanical strength even when used for a long time.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
Each component used in the examples and comparative examples is as follows.

Rubber component (A)
Natural rubber: “STR20” natural rubber made in Thailand Oil-extended styrene butadiene rubber: “JSR1723” manufactured by JSR Corporation
Weight average molecular weight (Mw) = 850,000
Styrene content = 23.5% by mass
Manufactured by emulsion polymerization
Oil content = 27.3%

Silica (B): “ULTRASIL7000GR”
Made by Evonik Degussa Japan
Wet silica: Average particle size 14nm
Modified polymer (C)
Modified polyfarnesene (C-1) to (C-4) and (C-17) produced in the following Production Examples 1 to 4 and 17
Modified farnesene copolymers (C-5) to (C-16) produced in the following Production Examples 5 to 16

Polyisoprene Polyisoprene (X-1) and (X-2) obtained in Comparative Production Examples 1 and 2 below
Polyfarnesene Polyfarnesene (X-3) obtained in Comparative Production Example 3 below

TDAE: “VivaTec500” H & R silane coupling agent (1): “Si75”
Siphonic coupling agent made by Evonik Degussa Japan (2): “Si69”
Evonik Degussa Japan anti-aging agent (1): “NOCRACK 6C”
Anti-aging agent manufactured by Ouchi Shinsei Chemical Co., Ltd. (2): “ANTAGE RD”
Kawaguchi Chemical Industry Co., Ltd. Wax: “Santite S” Seiko Chemical Co., Ltd.

Vulcanizing agent Sulfur (fine powder 200 mesh, manufactured by Tsurumi Chemical Co., Ltd.)
Vulcanization accelerator Vulcanization accelerator (1): "Noxeller NS-P"
Vulcanization accelerator made by Ouchi Shinsei Chemical Co., Ltd. (2): “Noxeller CZ-G”
Vulcanization accelerator made by Ouchi Shinsei Chemical Co., Ltd. (3): “Noxeller D”
Vulcanization accelerator made by Ouchi Shinsei Chemical Co., Ltd. (4): “Noxeller TBT-N”
Ouchi Shinsei Chemical Co., Ltd. Vulcanization Aid Stearic Acid: “Lunac S-20” Kao Corporation Zinc Hana: “Zinc Oxide” Sakai Chemical Industry Co., Ltd.

Production Example 1: Production of maleic anhydride-modified polyfarnesene (C-1) In a pressure-resistant container purged with nitrogen and dried, 274 g of hexane as a solvent and 1.2 g of n-butyllithium (17% by mass hexane solution) as an initiator After charging and heating to 50 ° C., 272 g of β-farnesene was added and polymerization was performed for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain unmodified polyfarnesene.
Next, 250 g of the unmodified polyfarnesene obtained in the pressure vessel, 0.25 g of NOCRACK 6C as an anti-aging agent, and 1.25 g of maleic anhydride were charged, purged with nitrogen, heated to 170 ° C., and reacted for 20 hours. As a result, maleic anhydride-modified polyfarnesene (C-1) having physical properties shown in Table 1 was obtained. The reaction rate of the modifier was 53%, and the amount of the functional group added to the modified polymer (C-1) was 0.3 part by mass with respect to 100 parts by mass of the unmodified polymer.

Production Example 2: Production of maleic anhydride-modified polyfarnesene (C-2) In a pressure-resistant container purged with nitrogen and dried, 5,755 g of hexane as a solvent and n-butyllithium (17% by mass hexane solution) as an initiator 26. After charging 5 g and raising the temperature to 50 ° C., 5,709 g of β-farnesene was added and polymerization was performed for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain unmodified polyfarnesene.
Next, 500 g of the unmodified polyfarnesene obtained in the pressure vessel, 0.5 g of NOCRACK 6C as an anti-aging agent, and 7.5 g of maleic anhydride were charged, purged with nitrogen, heated to 170 ° C., and reacted for 24 hours. By doing so, maleic anhydride-modified polyfarnesene (C-2) having the physical properties shown in Table 1 was obtained. The reaction rate of the modifier was 87%, and the amount of functional group added to the modified polymer (C-2) was 1.3 parts by mass with respect to 100 parts by mass of the unmodified polymer.

Production Example 3: Production of maleic anhydride-modified polyfarnesene (C-3) In a pressure-resistant container purged with nitrogen and dried, 5,755 g of hexane as a solvent and n-butyllithium (17% by mass hexane solution) as an initiator 26. After charging 5 g and raising the temperature to 50 ° C., 5,709 g of β-farnesene was added and polymerization was performed for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain unmodified polyfarnesene.
Next, 500 g of the unmodified polyfarnesene obtained in the pressure vessel, 0.5 g of NOCRACK 6C as an anti-aging agent, and 25 g of maleic anhydride are charged, and after purging with nitrogen, the temperature is raised to 170 ° C. and reacted for 24 hours. As a result, maleic anhydride-modified polyfarnesene (C-3) having physical properties shown in Table 1 was obtained. The reaction rate of the modifier was 94%, and the amount of functional group added to the modified polymer (C-3) was 4.7 parts by mass with respect to 100 parts by mass of the unmodified polymer.

Production Example 4: Production of maleic anhydride-modified polyfarnesene (C-4) In a pressure-resistant container purged with nitrogen and dried, 1,216 g of cyclohexane as a solvent and sec-butyllithium (10.5 mass% cyclohexane solution) as an initiator 42.6 g was charged and the temperature was raised to 50 ° C., 1,880 g of β-farnesene was added and polymerization was performed for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain unmodified polyfarnesene.
Next, 500 g of the unmodified polyfarnesene obtained in the pressure vessel, 0.5 g of NOCRACK 6C as an anti-aging agent, and 7.5 g of maleic anhydride were charged, purged with nitrogen, heated to 170 ° C., and reacted for 24 hours. As a result, maleic anhydride-modified polyfarnesene (C-4) having the physical properties shown in Table 1 was obtained. The reaction rate of the modifier was 94%, and the amount of the functional group added to the modified polymer (C-4) was 1.4 parts by mass with respect to 100 parts by mass of the unmodified polymer.

Comparative production example 1: Production of polyisoprene (X-1) A pressure-resistant container purged with nitrogen and dried was charged with 600 g of hexane and 13.9 g of n-butyllithium (17% by mass hexane solution) and heated to 70 ° C. Then, 1370 g of isoprene was added and polymerization was performed for 1 hour. After adding methanol to the obtained polymerization reaction solution, the polymerization reaction solution was washed with water. Water was separated, and the polymerization reaction solution was dried at 70 ° C. for 12 hours to obtain polyisoprene (X-1) having physical properties shown in Table 1.

Comparative Production Example 2: Production of polyisoprene (X-2) 600 g of hexane and 44.9 g of n-butyllithium (17% by mass hexane solution) were charged into a pressure vessel that had been purged with nitrogen and dried, and the temperature was raised to 70 ° C. Then, 2050 g of isoprene was added and polymerization was performed for 1 hour. After adding methanol to the obtained polymerization reaction solution, the polymerization reaction solution was washed with water. Water was separated, and the polymerization reaction solution was dried at 70 ° C. for 12 hours to obtain polyisoprene (X-2) having physical properties shown in Table 1.

In addition, the modified polymer (C), the weight average molecular weight (Mw) of polyisoprene, molecular weight distribution (Mw / Mn), melt viscosity, and the measuring method of the reaction rate of a modifier are as follows.
(Method of measuring weight average molecular weight and molecular weight distribution)
Mw and Mw / Mn of the modified polymer (C) and polyisoprene were determined by GPC (gel permeation chromatography) in terms of standard polystyrene equivalent molecular weight. The measuring apparatus and conditions are as follows.
・ Device: GPC device “GPC8020” manufactured by Tosoh Corporation
Separation column: “TSKgel G4000HXL” manufactured by Tosoh Corporation
Detector: “RI-8020” manufactured by Tosoh Corporation
・ Eluent: Tetrahydrofuran ・ Eluent flow rate: 1.0 ml / min ・ Sample concentration: 5 mg / 10 ml
-Column temperature: 40 ° C

(Measuring method of melt viscosity)
The melt viscosity at 38 ° C. of the modified polymer (C) was measured with a Brookfield viscometer (manufactured by BROOKFIELD ENGINEERING LABS. INC.).

(Method for measuring reaction rate of denaturant)
To 3 g of the sample after the denaturation reaction, 180 mL of toluene and 20 mL of ethanol were added and dissolved, and then neutralization titration with an ethanol solution of 0.1 N potassium hydroxide was performed to determine the acid value.
Acid value (mgKOH / g) = (A−B) × F × 5.661 / S
A: A drop amount of ethanol solution of 0.1N potassium hydroxide required for neutralization (mL)
B: 0.1N potassium hydroxide ethanol solution drop volume in a blank containing no sample (mL)
F: Potency of ethanol solution of 0.1N potassium hydroxide S: Weight of sample weighed (g)
The sample after the denaturation reaction was washed 4 times with methanol (5 mL relative to 1 g of the sample) to remove unreacted maleic anhydride, and then the sample was dried under reduced pressure at 80 ° C. for 12 hours. The acid value was determined by the method. The reaction rate of the modifier was calculated based on the following formula.
[Modification rate of modifier] = [Acid value after washing] / [Acid value before washing] × 100

Example 1 and Comparative Examples 1 and 2
According to the blending ratio (parts by mass) listed in Table 2, the rubber component (A), silica (B), modified polymer (C), polyisoprene, TDAE, vulcanization aid and anti-aging agent are each sealed. The mixture was put into a Banbury mixer and kneaded for 6 minutes so that the starting temperature was 75 ° C. and the resin temperature was 160 ° C., then taken out of the mixer and cooled to room temperature. Next, this mixture was put in a mixing roll, a vulcanizing agent and a vulcanization accelerator were added, and kneaded at 60 ° C. for 6 minutes to obtain about 1.2 kg of a rubber composition. The Mooney viscosity of the obtained rubber composition was measured by the following method.
The obtained rubber composition was press-molded (145 ° C., 45 minutes) to produce a vulcanized rubber sheet (thickness 2 mm), and the rolling resistance performance, hardness, and tensile breaking strength were evaluated based on the following methods. did. The results are shown in Table 2.
In addition, the measuring method of each evaluation is as follows.

-Rolling resistance performance A test piece of 40 mm length x 7 mm width was cut out from the rubber composition sheets produced in the examples and comparative examples, and measured using a dynamic viscoelasticity measuring device manufactured by GABO at a measurement temperature of 60 ° C and a frequency of 10 Hz. Tan δ was measured under the conditions of 10% static strain and 2% dynamic strain, and used as an index of rolling resistance. The numerical value of each Example and Comparative Example is a relative value when the value of Comparative Example 2 is set to 100. In addition, the rolling resistance performance of a rubber composition is so favorable that a numerical value is small.

・ Hardness (steering stability)
Using the rubber composition sheets prepared in Examples and Comparative Examples, the hardness was measured with a type A hardness meter in accordance with JIS K6253, and used as an index of flexibility. In addition, when a numerical value is smaller than 50, since the deformation | transformation of a tire is large when the said composition is used for a tire, steering stability deteriorates.

・ Tensile strength at break (mechanical strength)
Dumbbell-shaped test pieces were punched from the rubber composition sheets prepared in Examples and Comparative Examples according to JIS3, and the tensile strength at break was measured according to JIS K6251 using an Instron tensile tester. The numerical value of each Example and Comparative Example is a relative value when the value of Comparative Example 2 is set to 100. Note that the larger the numerical value, the better the breaking property.

  The rubber composition of Example 1 has good hardness and excellent rolling resistance performance and mechanical strength as compared with Comparative Examples 1 and 2 that do not contain the modified polymer (C). It can be used suitably.

Examples 2 to 4, Comparative Examples 3 and 4
According to the blending ratio (parts by mass) described in Table 3, the rubber component (A), silica (B), modified polymer (C), polyisoprene, TDAE, wax, vulcanization aid, and anti-aging agent, respectively. The mixture was put into a closed Banbury mixer and kneaded for 6 minutes so that the starting temperature was 75 ° C. and the resin temperature was 160 ° C., then taken out of the mixer and cooled to room temperature. Next, this mixture was put in a mixing roll, a vulcanizing agent and a vulcanization accelerator were added, and kneaded at 60 ° C. for 6 minutes to obtain about 1.3 kg of a rubber composition.
Further, the obtained rubber composition was press-molded (145 ° C., 30 minutes) to produce a vulcanized rubber sheet (thickness 2 mm), and the rolling resistance performance, hardness, and tensile breaking strength were evaluated based on the above methods. did. Moreover, abrasion resistance and an elastic modulus were evaluated based on the following method. The results are shown in Table 3.
In addition, the numerical values of the rolling resistance performance and the tensile strength at break in Table 3 are relative values when the value of Comparative Example 4 in Table 3 is 100.

-Elastic modulus A test piece of 40 mm length x 7 mm width was cut out from the vulcanized rubber sheet produced in Examples and Comparative Examples, and measured using a dynamic viscoelasticity measuring device manufactured by GABO at a measurement temperature of 25 ° C, a frequency of 10 Hz, and static. The storage elastic modulus E ′ was measured under the conditions of a strain of 10% and a dynamic strain of 2%, and used as an index of rigidity. The numerical value of each Example and Comparative Example is a relative value when the value of Comparative Example 4 is 100. In addition, the larger the numerical value, the smaller the deformation of the tire when the rubber composition is used for the tire, and the better the steering stability.

  The rubber compositions of Examples 2 to 4 have higher elastic modulus, excellent rolling resistance performance and hardness, and better mechanical strength than those of Comparative Examples 3 and 4 that do not contain the modified polymer (C). It can be suitably used as a rubber composition.

Production Example 5 Production of Maleic Anhydride Modified Farnesene-Butadiene Copolymer (C-5) In a pressure-resistant container purged with nitrogen and dried, 1,121 g of hexane as a solvent and sec-butyllithium (10.5 as an initiator) 49.2 g of a mass% cyclohexane solution) and the temperature was raised to 50 ° C., and then a previously prepared mixture of β-farnesene (c1) and butadiene (c2) (1,260 g of β-farnesene (c1) and butadiene (c2) ) 840 g was mixed in a cylinder) 1,430 g was added at 10 ml / min and polymerized for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain an unmodified farnesene-butadiene copolymer.
Next, 500 g of the unmodified farnesene-butadiene copolymer obtained in the pressure vessel, 0.5 g of Nocrack 6C as an anti-aging agent, and 25 g of maleic anhydride were charged, and after nitrogen substitution, the temperature was raised to 170 ° C. By reacting for 24 hours, a maleic anhydride-modified farnesene-butadiene copolymer (C-5) having physical properties shown in Table 4 was obtained. The reaction rate of the modifier was 96%, and the amount of functional group added to the modified polymer (C-5) was 4.8 parts by mass with respect to 100 parts by mass of the unmodified polymer.

Production Example 6 Production of Maleic Anhydride Modified Farnesene-Butadiene Copolymer (C-6) Into a pressure-resistant container purged with nitrogen and dried, 1,137 g of hexane as a solvent and sec-butyllithium (10.5 as an initiator) (Mass% cyclohexane solution) 32.8 g was charged, the temperature was raised to 50 ° C., and a mixture of β-farnesene (c1) and butadiene (c2) prepared in advance (1,260 g of β-farnesene (c1) and butadiene (c2) was prepared. ) 840 g was mixed in a cylinder) 1,430 g was added at 10 ml / min and polymerized for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain an unmodified farnesene-butadiene copolymer.
Next, 500 g of the unmodified farnesene-butadiene copolymer obtained in the pressure vessel, 0.5 g of Nocrack 6C as an anti-aging agent, and 25 g of maleic anhydride were charged, and after nitrogen substitution, the temperature was raised to 170 ° C. By reacting for 24 hours, a maleic anhydride-modified farnesene-butadiene copolymer (C-6) having physical properties shown in Table 4 was obtained. The reaction rate of the modifier was 97%, and the amount of the functional group added to the modified polymer (C-6) was 4.9 parts by mass with respect to 100 parts by mass of the unmodified polymer.

Production Example 7 Production of Maleic Anhydride Modified Farnesene-Butadiene Copolymer (C-7) In a pressure-resistant container purged with nitrogen and dried, 1,152 g of hexane as a solvent and sec-butyllithium (10.5 as an initiator) 18.5 g of a mass% cyclohexane solution) was heated to 50 ° C., and then prepared in advance was a mixture of β-farnesene (c1) and butadiene (c2) (1,170 g of β-farnesene (c1) and butadiene (c2). ) 780 g was mixed in a cylinder) 1,430 g was added at 10 ml / min and polymerized for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain an unmodified farnesene-butadiene copolymer.
Next, 500 g of the unmodified farnesene-butadiene copolymer obtained in the pressure vessel, 0.5 g of Nocrack 6C as an anti-aging agent, and 25 g of maleic anhydride were charged, and after nitrogen substitution, the temperature was raised to 170 ° C. By reacting for 24 hours, a maleic anhydride-modified farnesene-butadiene copolymer (C-7) having physical properties shown in Table 4 was obtained. The reaction rate of the modifier was 94%, and the amount of functional group added to the modified polymer (C-7) was 4.7 parts by mass with respect to 100 parts by mass of the unmodified polymer.

Production Example 8 Production of Maleic Anhydride Modified Farnesene-Butadiene Copolymer (C-8) In a pressure-resistant vessel purged with nitrogen and dried, 1,147 g of hexane as a solvent and sec-butyllithium (10.5 as an initiator) 22.3 g of a mass% cyclohexane solution), and the temperature was raised to 50 ° C., and then a mixture of β-farnesene (c1) and butadiene (c2) prepared in advance (1,520 g of β-farnesene (c1) and butadiene (c2) ) 380 g was mixed in a cylinder) 1,430 g was added at 10 ml / min and polymerized for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain an unmodified farnesene-butadiene copolymer.
Next, 500 g of the unmodified farnesene-butadiene copolymer obtained in the pressure vessel, 0.5 g of Nocrack 6C as an anti-aging agent, and 25 g of maleic anhydride were charged, and after nitrogen substitution, the temperature was raised to 170 ° C. By reacting for 24 hours, a maleic anhydride-modified farnesene-butadiene copolymer (C-8) having physical properties shown in Table 4 was obtained. The reaction rate of the modifier was 96%, and the amount of the functional group added to the modified polymer (C-8) was 4.8 parts by mass with respect to 100 parts by mass of the unmodified polymer.

Production Example 9 Production of Maleic Anhydride Modified Farnesene-Butadiene Copolymer (C-9) In a pressure-resistant container purged with nitrogen and dried, 1,136 g of hexane as a solvent and sec-butyllithium (10.5 as an initiator) (Mass% cyclohexane solution) 32.2 g was charged and the temperature was raised to 50 ° C., and then a pre-prepared mixture of β-farnesene (c1) and butadiene (c2) (1,000 g of β-farnesene (c1) and butadiene (c2) ) 1,000 g was mixed in a cylinder) 1,430 g was added at 10 ml / min and polymerized for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain an unmodified farnesene-butadiene copolymer.
Next, 500 g of the unmodified farnesene-butadiene copolymer obtained in the pressure vessel, 0.5 g of Nocrack 6C as an anti-aging agent, and 25 g of maleic anhydride were charged, and after nitrogen substitution, the temperature was raised to 170 ° C. By reacting for 24 hours, a maleic anhydride-modified farnesene-butadiene copolymer (C-9) having physical properties shown in Table 4 was obtained. The reaction rate of the modifier was 94%, and the amount of functional group added to the modified polymer (C-9) was 4.7 parts by mass with respect to 100 parts by mass of the unmodified polymer.

Production Example 10 Production of Maleic Anhydride Modified Farnesene-Butadiene Copolymer (C-10) In a pressure-resistant container purged with nitrogen and dried, 1,133 g of hexane as a solvent and sec-butyllithium (10.5 as an initiator) (Mass% cyclohexane solution) 36.9 g, heated to 50 ° C., and then prepared in advance, a mixture of β-farnesene (c1) and butadiene (c2) (390 g of β-farnesene (c1) and butadiene (c2) 1 , 560 g were mixed in a cylinder), 1,430 g was added at 10 ml / min and polymerized for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried at 70 ° C. for 12 hours to obtain an unmodified farnesene-butadiene copolymer.
Next, 500 g of the unmodified farnesene-butadiene copolymer obtained in the pressure vessel, 0.5 g of Nocrack 6C as an anti-aging agent, and 25 g of maleic anhydride were charged, and after nitrogen substitution, the temperature was raised to 170 ° C. By reacting for 24 hours, a maleic anhydride-modified farnesene-butadiene copolymer (C-10) having physical properties shown in Table 4 was obtained. The reaction rate of the modifier was 92%, and the amount of functional group added to the modified polymer (C-10) was 4.6 parts by mass with respect to 100 parts by mass of the unmodified polymer.

Production Example 11: 5.9 g of methanol was added to 315 g of the maleic anhydride-modified farnesene-butadiene copolymer (C-5) obtained in Production Example 5 and reacted at 80 ° C. for 6 hours to modify the monomethyl maleate ester. A farnesene-butadiene copolymer (C-11) was obtained.

Production Example 12: 5.9 g of methanol was added to 315 g of the maleic anhydride-modified farnesene-butadiene copolymer (C-6) obtained in Production Example 6 and reacted at 80 ° C. for 6 hours to modify the maleic acid monomethyl ester. A farnesene-butadiene copolymer (C-12) was obtained.

Production Example 13: 5.9 g of methanol was added to 315 g of the maleic anhydride-modified farnesene-butadiene copolymer (C-7) obtained in Production Example 7, and reacted at 80 ° C. for 6 hours to modify the maleic acid monomethyl ester. A farnesene-butadiene copolymer (C-13) was obtained.

Production Example 14: 5.9 g of methanol was added to 315 g of the maleic anhydride-modified farnesene-butadiene copolymer (C-8) obtained in Production Example 8, and reacted at 80 ° C. for 6 hours to modify the monomethyl maleate. A farnesene-butadiene copolymer (C-14) was obtained.

Production Example 15: 5.9 g of methanol was added to 315 g of the maleic anhydride-modified farnesene-butadiene copolymer (C-9) obtained in Production Example 9 and reacted at 80 ° C. for 6 hours to modify the monomethyl maleate ester. A farnesene-butadiene copolymer (C-15) was obtained.

Production Example 16: 5.9 g of methanol was added to 315 g of the maleic anhydride-modified farnesene-butadiene copolymer (C-9) obtained in Production Example 10 and reacted at 80 ° C. for 6 hours to modify the maleic acid monomethyl ester. A farnesene-butadiene copolymer (C-10) was obtained.

Production Example 17: 5.9 g of methanol was added to 315 g of maleic anhydride-modified polyfarnesene (C-4) obtained in Production Example 4 and reacted at 80 ° C. for 6 hours to give a maleic acid monomethyl ester-modified polyfarnesene (C-17). )

Comparative Production Example 3: Production of polyfarnesene (X-3) A pressure-resistant container purged with nitrogen and dried was charged with 1,392 g of cyclohexane and 8.0 g of sec-butyllithium (10.5 mass% cyclohexane solution), and 50 ° C. Then, 1,400 g of farnesene was added and polymerized for 1 hour. After adding methanol to the obtained polymerization reaction solution, the polymerization reaction solution was washed with water. Water was separated and the polymerization reaction solution was dried at 70 ° C. for 12 hours to obtain polyfarnesene (X-3) having physical properties shown in Table 4.

  The weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), and melt viscosity of the modified polymer (C) obtained in Production Examples 5 to 17 and the polyfarnesene obtained in Comparative Production Example 3 were the same as described above. Measured with Moreover, the measuring method of the glass transition temperature, the equivalent of a functional group, the amount of added functional groups, and the average number of functional groups per polymer molecule is as follows.

(Glass-transition temperature)
Ten mg of the modified farnesene polymer was sampled on an aluminum pan, and a thermogram was measured by a differential scanning calorimetry (DSC) under a heating rate condition of 10 ° C./min. The peak top value of DDSC was taken as the glass transition temperature.

(Equivalent functional group)
The sample after the denaturation reaction was washed with methanol four times (5 mL with respect to 1 g of the sample) to remove impurities, and then the sample was dried under reduced pressure at 80 ° C. for 12 hours. To 3 g of this sample, 180 mL of toluene and 20 mL of ethanol were added and dissolved, and then neutralization titration with an ethanol solution of 0.1 N potassium hydroxide was performed to determine the acid value.
Acid value (mgKOH / g) = (A−B) × F × 5.661 / S
A: A drop amount of ethanol solution of 0.1N potassium hydroxide required for neutralization (mL)
B: 0.1N potassium hydroxide ethanol solution drop volume in a blank containing no sample (mL)
F: Potency of ethanol solution of 0.1N potassium hydroxide S: Weight of sample weighed (g)

Next, the mass of the functional group contained per 1 g of the modified polymer (C) and the mass other than the functional group contained per 1 g (polymer main chain mass) were calculated from the acid value. The functional group equivalent (g / eq) was calculated from the following formula.
[Functional group mass per 1 g of polymer] = [Acid value] / [56.11] × [Functional group molecular weight] / 1000
[Polymer main chain mass per gram of polymer] = 1- [Functional group mass per gram of polymer]
[Equivalent functional group] = [polymer main chain weight per 1 g of polymer] / ([functional group weight per 1 g of polymer] / [functional group molecular weight]

(Amount of functional group added)
Based on the following formula, the amount of functional group (modifier amount) added to 100 parts by mass of the unmodified polymer was calculated [parts by mass].
[Amount of functional group added] = [Functional group mass per 1 g of polymer] / [Polymer main chain mass per 1 g] × 100

(Average number of functional groups per molecule of polymer)
Production Examples 4-9 or Production Example 10
To 3 g of the sample after the modification reaction obtained in Production Examples 4 to 9 or Production Example 10, 180 mL of toluene and 20 mL of ethanol were added and reacted at room temperature for 30 minutes. Thereafter, the solution was vacuum-dried at 60 ° C. for 12 hours, and the obtained sample was sampled using ¹ H-NMR (500 MHz) manufactured by JEOL Ltd. Sample / deuterated chloroform = 100 mg / 1 mL concentration, number of integrations 512 times, measurement temperature Measured at 30 ° C. The average number of functional groups per molecule of the modified polymer (C) was calculated from the area ratio of the peak derived from the methylene group of the ethyl ester in the obtained spectrum to the peak derived from the end of the polymer initiator.

Production Examples 11 to 16 or Production Example 17
Samples after the denaturation reaction obtained in Production Examples 11 to 16 or Production Example 17 using ¹ H-NMR (500 MHz) manufactured by JEOL Ltd., concentration of sample / deuterated chloroform = 100 mg / 1 mL, number of integrations 512 times, The measurement was performed at a measurement temperature of 30 ° C. The average number of functional groups per molecule of the modified polymer (C) was calculated from the area ratio of the peak derived from the methyl group of the methyl ester of the obtained spectrum to the peak derived from the end of the polymer initiator.

Examples 5-18, Comparative Examples 5 and 6
According to the blending ratio (parts by mass) described in Table 5-1 and Table 5-2, rubber component (A), silica (B), modified polymer (C), polyfarnesene, polyisoprene, TDAE, wax, vulcanization The auxiliary agent and the anti-aging agent were respectively put into a closed Banbury mixer and kneaded for 6 minutes so that the starting temperature was 75 ° C. and the resin temperature was 160 ° C., then taken out of the mixer and cooled to room temperature. Next, this mixture was put in a mixing roll, a vulcanizing agent and a vulcanization accelerator were added, and kneaded at 60 ° C. for 6 minutes to obtain about 1.3 kg of a rubber composition. About the rubber composition obtained in Examples 5-16, Mooney viscosity was evaluated based on the following method.
Further, the obtained rubber composition is press-molded (145 ° C., 30 minutes) to produce a vulcanized rubber sheet (thickness 2 mm). Based on the above methods, rolling resistance performance, hardness, tensile breaking strength, and elasticity Rate was evaluated. Moreover, abrasion resistance was evaluated based on the following method. The results are shown in Tables 5-1 and 5-2.
In addition, the numerical values of rolling resistance performance, tensile breaking strength, and elastic modulus in Table 5-1 and Table 5-2 are relative values when the value of Comparative Example 6 in Table 5-2 is set to 100.

Abrasion resistance According to JIS K 6264, the DIN wear amount at a wear distance of 40 m was measured under a load of 10 N, and the reciprocal of the DIN wear amount (1 / DIN wear amount) was used as an index of wear resistance. The numerical values of Examples and Comparative Examples in Table 5-1 and Table 5-2 are relative values when the value of Comparative Example 6 is set to 100. In addition, the larger the value, the smaller the amount of wear and the better the wear resistance.

-Mooney viscosity About the rubber composition before vulcanization obtained in the said Examples 5-16, Mooney viscosity (ML1 + 4) was measured at 100 degreeC as a processability parameter | index based on JISK6300. The value of each Example in Table 5-1 and Table 5-2 is a relative value when the value of Example 5 is set to 100. In addition, workability is so favorable that a numerical value is small.

The rubber compositions of Examples 5 to 18 have a high elastic modulus and good steering stability when used as vulcanized rubber as compared with Comparative Examples 5 and 6 that do not contain the modified polymer (C), and rolling resistance. Since it has excellent performance and hardness and good mechanical strength, it can be suitably used as a rubber composition for tires. Among them, the rubber compositions of Examples 5 to 16 containing butadiene as the monomer unit (c2) other than farnesene are superior in rolling resistance performance, elastic modulus, and wear resistance when used as a vulcanized rubber. I understand. It can also be seen that the rubber compositions of Examples 11 to 16 and Example 18 containing modified polymers modified with methanol after modification with maleic anhydride are particularly excellent in elastic modulus when used as vulcanized rubber.
Moreover, when Examples 8-10 and Examples 14-16 which changed content of monomer units (c2) other than farnesene in a modified polymer (C) were compared, the said monomer unit (c2) When the content of is 20 to 60% by mass, the Mooney viscosity is further reduced, which indicates that the processability of the rubber composition is improved.

Claims (11)

  100 parts by mass of a rubber component (A) comprising a rubber component (A) comprising at least one of synthetic rubber and natural rubber, silica (B), and a modified polymer (C) of farnesene modified by introducing a functional group A rubber composition containing 20 to 150 parts by mass of silica (B) with respect to parts, and 2 to 10 parts by mass of the modified polymer (C) with respect to 100 parts by mass of silica (B).   The rubber composition according to claim 1, wherein the functional group of the modified polymer (C) is one or two or more selected from a carboxy group, an amino group, a hydroxy group, and a functional group derived from an acid anhydride. .   The rubber composition according to claim 1 or 2, wherein the silica (B) has an average particle size of 0.5 to 200 nm.   The rubber composition according to any one of claims 1 to 3, wherein the modified polymer (C) at 38 ° C has a melt viscosity of 0.1 to 3,000 Pa · s.   The rubber composition according to any one of claims 1 to 4, wherein the modified polymer (C) has a weight average molecular weight (Mw) of 2,000 to 500,000.   The modified polymer (C) is a copolymer composed of a monomer unit (c1) derived from β-farnesene and a monomer unit (c2) derived from a monomer other than β-farnesene. The rubber composition according to any one of claims 1 to 5.   The rubber composition in any one of Claims 1-6 which contains 0.1-30 mass parts of silane coupling agents with respect to 100 mass parts of said silica (B).   The rubber composition according to any one of claims 1 to 7, wherein the rubber component (A) is at least one of styrene butadiene rubber and natural rubber.   The rubber composition according to claim 8, wherein the styrene-butadiene rubber has a weight average molecular weight of 100,000 to 2.5 million.   The rubber composition according to claim 8 or 9, wherein the styrene-butadiene rubber has a styrene content of 0.1 to 70 mass%.   A tire using at least a part of the rubber composition according to claim 1.